In the ever increasing usage of digital electronic components and equipment, such as minicomputers and microprocessors, one of the impediments to even wider applications thereof is the cost factor inherent in interfacing techniques with the analog world. Interfacing apparatus commonly represent the most significant cost in a total system.
Transducers typically employ a condition responsive element which produces an analog voltage as a function of the condition being sensed. In order to use this analog voltage in conjunction with microprocessors, etc., an A/D converter is necessary to translate the analog voltage to a digital value. Alternatively, a comparator could be used to produce an output signal when the analog voltage exceeds a reference level.
The area of temperature control and/or indication in automotive applications is an example of a field in which the high cost and necessity of interfacing devices has deterred usage of digital electronic equipment.